Detection of highly lethal H5N2 virus spurs fears that the disease has returned to U.S.

A highly lethal form of avian flu was detected in a wild mallard duck in Alaska, U.S. Department of Agriculture officials said Friday, reigniting fears of a return of the virus that hasn't been spotted in the country for more than a year.

It is the same strain that affected more than 50 million birds in 15 different states last year. Known as the H5N2 virus, it was detected in a state wildlife refuge in Fairbanks, officials said.